The TCP display on the client is the round trip time (RTT) This is sampled per the network stack.
Note that with 2.0.14 and the --trip-times option there is an application level latency as well. It's the client's write() start time to the server's final read of that write. For --isochronous the latencies are per each frame or burst. For many cases what users care most about is end/end or application to application latency. It's network stack engineers that typically care about RTT Bob On Thu, Apr 16, 2020 at 12:00 PM Andrew Morcos <andrewmor...@outlook.com> wrote: > Hello M. McMahon > Thank you for your answer! > Concerning TCP packets, does it find the latency based on the time the > clients receives an acknowledgment? > Thank you! > > ANDREW MORCOS > > > Sent from my Huawei phone > > > -------- Original message -------- > From: Bob McMahon <bob.mcma...@broadcom.com> > Date: Thu, Apr 16, 2020, 8:57 PM > To: Andrew Morcos <andrewmor...@outlook.com> > Cc: iperf-users@lists.sourceforge.net > Subject: Re: [Iperf-users] Iperf latency measures > > The UDP latency assumes the two clocks are synchronized. The GPS atomic > clocks are suggested as a common reference. IEEE 1588 or Precision Time > Protocol (PTP) is suggested (over things like network time protocol NTP) to > distribute a reference clock. For a bench test environment one could use > the clock on a device and distribute it to the other using(s) PTP. A final > option is to use your own local oscillator and distribute that. I use oven > controlled oscillators (OCXO) by spectracom, e.g. their tsync pcie cards. > > Note: In 2.0.14, currently under development, these values will own show > up if the --trip-times option is set on the client. This basically > indicates to iperf that the user is claiming the clocks have somehow been > synchronized. There are a bunch more latency related features as well. > videos > can be found here > <https://www.youtube.com/channel/UCaqlH3a442xaZ9humrxRHGQ/> > > Bob > > On Thu, Apr 16, 2020 at 10:35 AM Andrew Morcos <andrewmor...@outlook.com> > wrote: > > Hello everyone, > > I have a question concerning how Iperf can determine some values. > So when using Iperf for capturing network information such as throuput, > packets loss etc.. There's an option "-e" that gives as an output the > LATENCY as well (average/max/min RTT). It works as well for UDP packets. > Does anyone know how could Iperf measure LATENCY for UDP packets since UDP > packets are unacknowledged? > > Thank you. > > Andrew Morcos > > > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon> > Virus-free. > www.avast.com > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link> > <#m_-3194983896188525430_m_3408531035212424192_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > _______________________________________________ > Iperf-users mailing list > Iperf-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/iperf-users > >
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